I added a Film Grain effect. It supports different approaches used in digital photography, films and games. Except simple noise, almost all modes base upon actual film grain samples, as a texture or a video stream. Following is a screenshot, which hardly captures the effect - you have to run the demo in order to recognize the differences; the download is in the first post of this thread.

Film Grain effect:


The first mode is procedural and calculates for each pixel random noise. The other modes tile or scale a grain-texture onto the screen in each different manners. A stream-mode takes a video file from actual film grain footage and streams it on the screen which is done pretty often in the film industry. You can buy footage at Pond5, iStockphoto or Cinegrain.com. Included in the download is a free grain sample.